That's an interesting question regarding the spotting scope Bushy. It is little known that in the UKicon No4T CES that it wasn't always a Sct Reg Scope either. There were several types including the Tele GS, The Tele Signalling, Tele Admiralty Patt and in some, said to be those fitted out by/for the RAF, the little B&C x20 pre-war Brittanic telescope. But for the L42's it was always (?) the Sct Reg Tele.